Just as if a fox had got into the hen-house in the dead of night, the 1,000 Guineas betting market was all of a-flutter early yesterday. For more than two hours, starting just before five o'clock, the price of the hot favourite Rainbow View began, mysteriously, to lengthen on the online exchange Betfair, eventually trading at 9-1. Slightly headlessly, some of the conventional firms temporarily suspended trading after they picked up the drift, sometimes an indication that all may not be well.

But the chicks were settled firmly back on their perches after firstly, Rainbow View sparkled in her final serious workout ahead of Sunday's Rowley Mile showpiece and secondly, the name of Fantasia, likewise trained by John Gosden and owned by George Strawbridge and who would have been a more than competent supersub, did not appear among the race's penultimate confirmations.

Gosden assured punters that Rainbow View is in the rudest of health, describing the betting flap as "completely bizarre" after witnessing his charge impress on the Al Bahathri gallop near her Newmarket stable. "She worked this morning and worked particularly well," he said yesterday. "I am very happy with her indeed."

By midday Rainbow View was queen of the bookies' lists again. Her brief dethronement may have been the result of a computer programming glitch in a single Betfair account and although the amounts traded – totalling just over £8,000 – are relatively small beer in professional punting terms, some backers may have secured a bargain. "Who knows why the individual in question laid a fit and healthy genuine 6-4 chance out to 9-1," said the firm's Tony Calvin, "but one explanation could be that it was a malfunctioning automated trading system."

The presence of a hot-shot – Rainbow View shortened to a general 5-4 after the withdrawal of her stablemate – has not proved a deterrent to potential rivals, with 21 fillies still possible runners in the 196th edition of their Guineas. Fantasia apart, the notable absentee was Sariska, who will have her Oaks prep in the Musidora Stakes at York.

Twenty-four colts are still in the mix for a much more open-looking 201st 2,000 Guineas on Saturday, including yesterday's sole supplementary entry Ouqba, put in the race at a cost of £30,000.

Some rain fell in Newmarket yesterday, but not much and the ground remains good to firm, which is little comfort for supporters of Delegator, the 3-1 market leader with big-race sponsors Stan James, after warnings from trainer Brian Meehan that the colt would not run on ground judged too fast. There is also a watching brief over the perceived Ballydoyle number one Rip Van Winkle, challenging for favouritism; he suffered a stone bruise yesterday, though is still thought likely to be ready for his big day.

But before the first Group 1 contests of the domestic Flat programme comes a week of glittering top-level action at the jumpers' last hurrah, the Punchestown festival. Today in Co Kildare the focus is on one star performer of the present and two with gilded promise for the future.

Paul Nicholls and Clive Smith have decided to treat Irish fans to a first sighting of dual Queen Mother Champion Chase hero Master Minded, who signs off until next winter with what should be a lap of honour over his favourite two-mile trip. In the Grade 1 novices hurdle, Hurricane Fly – many people's idea of next year's senior champion – tests his credentials against Cheltenham winner Go Native, and in the novices chase his fellow Willie Mullins inmate Cooldine, already backed for next year's Gold Cup, has a showdown with hat-trick seeking Joncol.